Xadok's Megas

Added mega haxorus

Changed the custom model data from 1, 2 etc. to niche numbers in the thousands to prevent overlapping data with other mega datapacks. This will cause the sprites of mega stones crafted in previous versions to default to popped chorus fruit but (should) remain functional. Its a small inconvenience for the 11 downloaders of the early versions but necessary for the growth of the datapack and preventing future issues.